Sir William Herschel, born November 15, 1738, was known for many things. He wrote symphonies and taught music. He was also an astronomer that built telescopes and discovered Uranus as a planet. And if that wasn't enough, he also set the stage for modern day thermography by being the first to observe the “dark heat” adjacent to the visible portion of the electromagnetic spectrum that we all now call infrared radiation.
Herschel’s famous experiment involved measuring the temperature of various visible light colors created by sunlight that passed through a prism (image, seen here) he had set-up in his laboratory. Most might be surprised to know that the experiment was originally devised to help him find filters for his telescope that would not be heated by the sun and was not an attempt to locate this energy.
As he worked, the sun’s position in the sky of course changed until the area past the red portion of visible light caused the temperature to register warmer on one of his thermometers. Although it would be about another 150 years or so before the first infrared images were created, Herschel’s experiment, and discovery of infrared radiation, is where everything got started.
When you pick up your thermal imager today, take a moment to appreciate where we are with this remarkable technology. We have arrived here thanks to the efforts of many great minds, not the least of whom is Sir William Herschel. Happy Birthday!
In honor of this day, The Snell Group is pleased to offer a free viewing of the webinar “A Brief History of Infrared Thermography,” narrated by Professor Francis Ring of the William Herschel Society, which includes additional background on the life of Herschel. Simply call 1.800.636.9820 and mention this blog post to receive your coupon to watch the webinar for free. Enjoy!